Nikolay N. Ponomarenko Vladimir V. Lukin Karen O. Egiazarian Jaakko Astola Benoit Vozel Kacem Chehdi Hybrid Sigma Filter for Processing Images Corrupted by Multiplicative Noise. 46-54 2006 conf/acivs/2006 ACIVS http://dx.doi.org/10.1007/11864349_5 db/conf/acivs/acivs2006.html#PonomarenkoLEAVC06